Editor’s Choice Articles

The effects of climate change on agricultural systems raise important uncertainties about the future productivity and suitability of crops, especially in areas suffering from intense environmental changes. Olive groves occupy Mediterranean areas characterized by seasonal temporary droughts, which cause this cultivation to be highly dependent on local microclimatic conditions. Olive crop production can be reliably estimated using pollen intensity metrics together with post-pollination environmental conditions. In this study, we applied this kind of statistics-based models to identify the most relevant meteorological variables during the post-pollination periods for olive fruit production. Olive pollen time-series for the period of 1999–2012 was analyzed in 16 Italian provinces. Minimum and maximum temperature during spring and summer (March–August) showed a negative relationship with olive production, while precipitation always showed a positive correlation. The increase in aridity conditions observed in areas of Italy during the summer represents an important risk of decreasing olive crop production. The effect of climate change on the olive production trend is not clear because of the interactions between human and environmental factors, although some areas might show an increase in productivity in the near future under different climate change scenarios. However, as more drastic changes in temperature or precipitation take place, the risk to olive production will be considerably greater. Full article

The recent proliferation of cohort studies of long-term exposure to outdoor fine particulate air pollution and mortality has led to a significant increase in knowledge about this important global health risk factor. As scientific knowledge has grown, mortality relative risk estimators for fine particulate matter have evolved from simple risk models based on a single study to complex, computationally intensive, integration of multiple independent particulate sources based on nearly one hundred studies. Since its introduction nearly 10 years ago, the integrated exposure-response (IER) model has become the state-of-the art model for such estimates, now used by the Global Burden of Disease Study (GBD), the World Health Organization, the World Bank, the United States Environmental Protection Agency’s benefits assessment software, and scientists worldwide to estimate the burden of disease and examine strategies to improve air quality at global, national, and sub-national scales for outdoor fine particulate air pollution, secondhand smoke, and household pollution from heating and cooking. With each yearly update of the GBD, estimates of the IER continue to evolve, changing with the incorporation of new data and fitting methods. As the number of outdoor fine particulate air pollution cohort studies has grown, including recent estimates of high levels of fine particulate pollution in China, new estimators based solely on outdoor fine particulate air pollution evidence have been proposed which require fewer assumptions than the IER and yield larger relative risk estimates. This paper will discuss the scientific and technical issues analysts should consider regarding the use of these methods to estimate the burden of disease attributable to outdoor fine particulate pollution in their own settings. Full article

Surface-level ozone (O₃) continues to be a significant health risk in the Greater Toronto Hamilton Area (GTHA) of Canada even though precursor emissions in the area have decreased significantly over the past two decades. In July 2015, Environment and Climate Change Canada (ECCC) led an intensive field study coincident with Toronto hosting the 2015 Pan American Games. During the field study, the daily 1-h maximum O₃ standard (80 ppbv) was exceeded twice at a measurement site in North Toronto, once on July 12 and again on July 28. In this study, ECCC’s 2.5-km configuration of the Global Environmental Multi-scale (GEM) meteorological model was combined with the Modelling Air-quality and CHemistry (MACH) on-line atmospheric chemistry model and the Town Energy Balance (TEB) urban surface parameterization to create a new urban air quality modelling system. In general, the model results showed that the nested 2.5-km grid-spaced urban air quality model performed better in statistical scores compared to the piloting 10-km grid-spaced GEM-MACH model without TEB. Model analyses were performed with GEM-MACH-TEB for the two exceedance periods. The local meteorology for both cases consisted of light winds with the highest O₃ predictions situated along lake-breeze fronts. For the July 28 case, O₃ production sensitivity analysis along the trajectory of the lake-breeze circulation showed that the region of most efficient O₃ production occurred in the updraft region of the lake-breeze front, as the precursors to O₃ formation underwent vertical mixing. In this updraft region, the ozone production switches from volatile organic compound (VOC)-sensitive to NOx-sensitive, and the local net O₃ production rate reaches a maximum. This transition in the chemical regime is a previously unidentified factor for why O₃ surface-level mixing ratios maximize along the lake-breeze front. For the July 12 case, differences between the model and observed Lake Ontario water temperature and the strength of lake-breeze opposing wind flow play a role in differences in the timing of the lake-breeze, which impacts the predicted location of the O₃ maximum north of Toronto. Full article

Smart farming based on Internet of Things (IoT) technologies enables crop farmers to collect real-time data related to irrigation and plant protection processes, aiming to increase production volume, improve product quality, and predict diseases, while optimizing resources and farming processes. IoT devices can collect vast amounts of environmental, soil, and crop performance data, thus building time series data that can be analyzed to forecast and compute recommendations and deliver critical information to farmers in real time. In this sense, the added-value from the farmers’ perspective is that such smart farming techniques have the potential to deliver a more sustainable agricultural production, based on a more precise and resource-efficient approach in the complex and versatile agricultural environment. The aim of this study is to investigate possible advantages of applying the Smart Farming as a Service (SFaaS) paradigm, aiming to support small-scale farmers, by taking over the technological investment burden and offering next generation farming advice through the combined utilization of heterogeneous information sources. The overall results of the pilot application demonstrate a potential reduction of up to 22% on total irrigation needs and important optimization opportunities on pesticides use efficiency. The current work offers opportunities for innovation targeting and climate change adaptation options (new agricultural technologies), and could help farmers to reduce their ecological footprint. Full article

This study presents features of airborne culturable bacteria and fungi from three different sites (Lanzhou; LZ; 1520 m ASL, Lhasa; LS; 3640 m ASL and Qomolangma; ZF; 4276 m ASL) representing urban (LZ and LS) and remote sites (ZF) over the Tibetan Plateau (TP). Total suspended particle (TSP) samples were collected with an air sampler (Laoying 2030, China) on a quartz filter. Community structures of bacteria and fungi were studied and compared among three different locations. The average levels of bacterial load in the outdoor air ranged from approximately 8.03 × 10¹ to 3.25 × 10² CFU m^–3 (Colony forming unit per m³). However, the average levels of fungal loads ranged from approximately 3.88 × 10⁰ to 1.55 × 10¹ CFU m⁻³. Bacterial load was one magnitude higher at urban sites LZ (2.06 × 10²–3.25 × 10² CFU m⁻³) and LS (1.96 × 10²–3.23 × 10² CFU m⁻³) compared to remote sites ZF (8.03 × 10¹–9.54 × 10¹ CFU m⁻³). Similarly, the maximum fungal load was observed in LZ (1.02 × 10¹–1.55 × 10¹ CFU m⁻³) followed by LS (1.03 × 10¹–1.49 × 10¹ CFU m⁻³) and ZF (3.88 × 10⁰–6.26 × 10⁰ CFU m⁻³). However, the maximum microbial concentration was observed on the same day of the month, corresponding to a high dust storm in Lanzhou during the sampling period. The reported isolates were identified by phylogenetic analysis of 16S rRNA genes for bacteria and ITS sequences for fungi amplified from directly extracted DNA. Bacterial isolates were mostly associated with Proteobacteria, Eurotiomycetes and Bacillus, whereas fungal isolates were mostly Aspergillus and Alternaria. Overall, this is a pioneer study that provides information about the airborne microbial concentration and composition of three sites over the TP region depending on environmental parameters. This study provided preliminary insight to carry out more advanced and targeted analyses of bioaerosol in the sites presented in the study. Full article

Scientific evidence spanning experimental and epidemiologic studies has shown that air pollution exposures can lead to a range of health effects. Quantitative approaches that allow for the estimation of the adverse health impacts attributed to air pollution enable researchers and policy analysts to convey the public health impact of poor air quality. Multiple tools are currently available to conduct such analyses, which includes software packages designed by the World Health Organization (WHO): AirQ+, and the U.S. Environmental Protection Agency (U.S. EPA): Environmental Benefits Mapping and Analysis Program—Community Edition (BenMAP—CE), to quantify the number and economic value of air pollution-attributable premature deaths and illnesses. WHO’s AirQ+ and U.S. EPA’s BenMAP—CE are among the most popular tools to quantify these effects as reflected by the hundreds of peer-reviewed publications and technical reports over the past two decades that have employed these tools spanning many countries and multiple continents. Within this paper we conduct an analysis using common input parameters to compare AirQ+ and BenMAP—CE and show that the two software packages well align in the calculation of health impacts. Additionally, we detail the research questions best addressed by each tool. Full article

In late 2019, the Intergovernmental Panel on Climate Change (IPCC) released their much-awaited Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC). High mountain areas, polar regions, low-lying islands and coastal areas, and ocean and marine ecosystems, were separately dealt by experts to reveal the impacts of climate change on these regions, as well as the responses of the natural and human systems inhabiting or related to these regions. The tourism sector was found, among the main systems, influenced by climate change in the oceanic and cryospheric environments. In this study, we deepen the understanding of tourism and climate interrelationships in the polar regions. In doing so, we step outside the climate resilience of polar tourism paradigm and systematically assess the literature in terms of its gaps relating to an extended framework where the impacts of tourism on climate through a combined and rebound effects lens are in question as well. Following a systematic identification and screening on two major bibliometric databases, a final selection of 93 studies, spanning the 2004–2019 period, are visualized in terms of their thematic and co-authorship networks and a study area based geobibliography, coupled with an emerging hot spots analysis, to help identify gaps for future research. Full article

In the present study, the daily dose in terms of submicron particle surface area received by children attending schools located in three different areas (rural, suburban, and urban), characterized by different outdoor concentrations, was evaluated. For this purpose, the exposure to submicron particle concentration levels of the children were measured through a direct exposure assessment approach. In particular, measurements of particle number and lung-deposited surface area concentrations at “personal scale” of 60 children were performed through a handheld particle counter to obtain exposure data in the different microenvironments they resided. Such data were combined with the time–activity pattern data, characteristics of each child, and inhalation rates (related to the activity performed) to obtain the total daily dose in terms of particle surface area. The highest daily dose was estimated for children attending the schools located in the urban and suburban areas (>1000 mm²), whereas the lowest value was estimated for children attending the school located in a rural area (646 mm²). Non-school indoor environments were recognized as the most influential in terms of children’s exposure and, thus, of received dose (>70%), whereas school environments contribute not significantly to the children daily dose, with dose fractions of 15–19% for schools located in urban and suburban areas and just 6% for the rural one. Therefore, the study clearly demonstrates that, whatever the school location, the children daily dose cannot be determined on the basis of the exposures in outdoor or school environments, but a direct assessment able to investigate the exposure of children during indoor environment is essential. Full article

A model inter-comparison of secondary pollutant simulations over urban areas in Japan, the first phase of Japan’s study for reference air quality modeling (J-STREAM Phase I), was conducted using 32 model settings. Simulated hourly concentrations of nitric oxide (NO) and nitrogen dioxide (NO₂), which are primary pollutant precursors of particulate matter with a diameter of 2.5 µm or less (PM_2.5), showed good agreement with the observed concentrations, but most of the simulated hourly sulfur oxide (SO₂) concentrations were much higher than the observations. Simulated concentrations of PM_2.5 and its components were compared to daily observed concentrations by using the filter pack method at selected ambient air pollution monitoring stations (AAPMSs) for each season. In general, most models showed good agreement with the observed total PM_2.5 mass concentration levels in each season and provided goal or criteria levels of model ensemble statistics in warmer seasons. The good performances of these models were associated with the simulated reproducibility of some dominant components, sulfates (SO₄²⁻) and ammonium (NH₄⁺). The other simulated PM_2.5 components, i.e., nitrates (NO₃⁻), elemental carbon (EC), and organic carbon (OC), often show clear deviations from the observations. The considerable underestimations (approximately 30 µg/m³ for total PM_2.5) of all participant models found on heavily polluted days with approximately 40–50 µg/m³ for total PM_2.5 indicated some problems in the simulated local meteorology such as the atmospheric stability. This model inter-comparison suggests that these deviations may be owing to a need for further improvements both in the emission inventories and additional formation pathways in chemical transport models, and meteorological conditions also require improvement to simulate elevated atmospheric pollutants. Additional accumulated observations are likely needed to further evaluate the simulated concentrations and improve the model performance. Full article

An improved approach to derive pseudo water vapor mass mixing ratio and in- cloud potential temperature was developed in this paper to better initialize numerical weather prediction (NWP) and build convective-scale predictions of severe weather events. The process included several steps. The first was to identify areas of deep moist convection, utilizing Vertically Integrated Liquid water (VIL) derived from a mosaicked 3D radar reflectivity field. Then, pseudo- water vapor and pseudo- in- cloud potential temperature observations were derived based on the VIL. For potential temperature, the latent heat initialization for stratiform cloud and moist adiabatic initialization for deep moist convection were used based on a cloud analysis method. The third step was to assimilate the derived pseudo- water vapor and potential temperature observations, together with radar radial velocity and reflectivity into a convective-scale NWP model during data assimilation cycles spanning several hours. Finally, 3-h forecasts were launched each hour during the data assimilation period. The effects of radar data and pseudo- observation assimilation on the prediction of rainfall associated with convective systems surrounding the Meiyu front in 2018 were explored using two real cases. Two sets of experiments, each including several experiments in each real case, were designed to compare the effects of assimilation radar and pseudo- observations on the ensuing forecasts. Relative to the control experiment without data assimilation and radar experiment, the analyses and forecasts of convections were found to be improved for the two Meiyu front cases after pseudo- water vapor and potential temperature information was assimilated. Full article

The ozone layer is well observed since the 1930s from the ground and, since the 1980s, by satellite-based instruments. The evolution of ozone in the past is important because of its dramatic influence on the biosphere and humans but has not been known for most of the time, except for some measurements of near-surface ozone since the end of the 19th century. This gap can be filled by either modeling or paleo reconstructions. Here, we address ozone layer evolution during the early 20th century. This period was very interesting due to a simultaneous increase in solar and anthropogenic activity, as well as an observed but not explained substantial global warming. For the study, we exploited the chemistry-climate model SOCOL-MPIOM driven by all known anthropogenic and natural forcing agents, as well as their combinations. We obtain a significant global scale increase in the total column ozone by up to 12 Dobson Units and an enhancement of about 20% of the near-surface ozone over the Northern Hemisphere. We conclude that the total column ozone changes during this period were mainly driven by enhanced solar ultra violet (UV) radiation, while near-surface ozone followed the evolution of anthropogenic ozone precursors. This finding can be used to constrain the solar forcing magnitude. Full article

This study devises a novel approach for defining extreme weather events and assessing their effects on human participation in recreation and tourism, based on a case study of attendance at the Toronto Zoo (Toronto, ON, Canada). Daily zoo attendance data from 1999 to 2018 was obtained and analyzed in connection with daily weather data from local weather stations for the maximum temperature, minimum temperature, total precipitation, and maximum wind speed. The “climatic distance” method, used for evaluating representative weather stations for case studies in applied climatology, was employed to rank and select surrounding weather stations that most accurately captured daily weather observations recorded at the Toronto Zoo from 1990 to 1992. Extreme weather events can be defined as lying in the outermost (most unusual) 10 percent of a place’s history. Using this definition as the foundation, a percentile approach was developed to identify and assess the effects of extreme weather events across the following thresholds: the 99th percentile, the 95th percentile, and the 90th percentile, as well as less than the 1st percentile, less than the 5th percentile, and less than the 10th percentile. Additionally, revealed, theoretical, and binary thresholds were also assessed to verify their merit and determine their effects, and were compared to the extreme weather events defined by the percentiles approach. Overall, extreme daily weather events had statistically significant negative effects on zoo attendance in Toronto, apart from a few cases, such as the positive effect of usually warm daytime temperatures in the winter and usually cool nighttime temperatures in the summer. The most influential weather event across all seasons was extremely hot temperatures, which has important implications for climate change impact assessments. Full article

In recent years, citizens’ attention towards air quality and pollution has increased significantly, and nowadays, odor pollution related to different industrial activities is recognized as a well-known environmental issue. For this reason, odors are subjected to control and regulation in many countries, and specific methods for odor measurement have been developed and standardized over the years. This paper, conceived within the H2020 D-NOSES project, summarizes odor measurement techniques, highlighting their applicability, advantages, and limits, with the aim of providing experienced as well as non-experienced users a useful tool that can be consulted in the management of specific odor problems for evaluating and identifying the most suitable approach. The paper also presents relevant examples of the application of the different methods discussed, thereby mainly referring to scientific articles published over the last 10 years. Full article

A chemistry–climate model of the lower and middle atmosphere is used to compare the role of natural and anthropogenic factors in the observed variability of stratospheric ozone. Numerical experiments have been carried out on several scenarios of separate and combined effects of solar activity, stratospheric aerosol, sea surface temperature, greenhouse gases, and ozone-depleting substances emissions on ozone for the period from 1979 to 2020. Simulations for the past and present periods are compared to the results of ground-based and satellite observations. Estimates of observed trends in column total ozone for the entire period 1980–2018 and separately for the late twentieth and early twenty-first century are presented. Full article

In most countries, PMV is the reference index for the assessment of thermal comfort conditions in mechanically conditioned environments. It is also the basis to settle input values of the operative temperature for heating and cooling load calculations, sizing of equipment, and energy calculations according to EN 16798-1 and 16798-2 Standards. Over the years, great effort has been spent to study the reliability of PMV, whereas few investigations were addressed to its calculation. To study this issue, the most significant apps devoted to its calculation have been compared with a reference software compliant with EN ISO 7730 and the well-known ASHRAE Thermal Comfort Tool. It has been revealed that only few apps consider all six variables responsible for the thermal comfort. Relative air velocity is not considered by ASHRAE Thermal Comfort Tool and, finally, the correction of basic insulation values due to body movements introduced by EN ISO 7730 and EN ISO 9920 Standards has only been considered in one case. This implies that most software and apps for the calculation of PMV index should be used with special care, especially by unexperienced users. This applies to both research and application fields. Full article

Atmospheric particle-bound mercury (PHg) quantification, at a pg m⁻³ level, has been assessed in particulate matter samples (PM₁₀) at several sites (industrial, urban and sub-urban sites) of Atlantic coastal European region during 13 months by using a direct thermo-desorption method. Analytical method validation was assessed using 1648a and ERM CZ120 reference materials. The limits of detection and quantification were 0.25 pg m⁻³ and 0.43 pg m⁻³, respectively. Repeatability of the method was generally below 12.6%. PHg concentrations varied between 1.5–30.8, 1.5–75.3 and 2.27–33.7 pg m⁻³ at urban, sub-urban and industrial sites, respectively. PHg concentration varied from 7.2 pg m⁻³ (urban site) to 16.3 pg m⁻³ (suburban site) during winter season, while PHg concentrations varied from 9.9 pg m⁻³ (urban site) to 19.3 pg m⁻³ (suburban site) during the summer. Other trace elements, major ions, black carbon (BC) and UV-absorbing particulate matter (UV PM) was also assessed at several sites. Average concentrations for trace metals (Al, As, Bi, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Si, Sr, V and Zn) ranged from 0.08 ng m⁻³ (Bi) at suburban site to 1.11 µg m⁻³ (Fe) at industrial site. Average concentrations for major ions (including Na⁺, K⁺, Ca²⁺, NH₄⁺, Mg²⁺, Cl⁻, NO₃⁻ and SO₄²⁻) ranged from 200 ng m⁻³ (K⁺) to 5332 ng m⁻³ (SO₄²⁻) at urban site, 166 ng m⁻³ (Mg²⁺) to 4425 ng m⁻³ (SO₄²⁻) at suburban site and 592 ng m⁻³ (K⁺) to 5853 ng m⁻³ (Cl⁻) at industrial site. Results of univariate analysis and principal component analysis (PCA) suggested crustal, marine and anthropogenic sources of PHg in PM₁₀ at several sites studied. Toxicity prediction of PHg, by using hazard quotient, suggested no non-carcinogenic risk for adults. Full article

We present a simple algorithm that calculates the cloud occurrence frequency at an altitude site using automatic camera image analysis. This algorithm was applied at the puy de Dôme station (PUY, 1465 m. a.s.l., France) over 2013–2018. Cloud detection thresholds were determined by direct comparison with simultaneous in situ cloud probe measurements (particulate volume monitor (PVM) Gerber). The cloud occurrence frequency has a seasonal cycle, with higher values in winter (60%) compared to summer (24%). A cloud diurnal cycle is observed only in summer. Comparisons with the larger scale products from satellites and global model reanalysis are also presented. The NASA cloud-aerosol transport system (CATS) cloud fraction shows the same seasonal and diurnal variations and is, on average, 11% higher. Monthly variations of the ECMWF ERA-5 fraction of cloud cover are also highly correlated with the camera cloud occurrence frequency, but the values are 19% lower and up to 40% for some winter months. The METEOSAT-SEVIRI cloud occurrence frequency also follows the same seasonal cycle but with a much smaller decrease in summer. The all-sky imager cloud fraction (CF) presents larger variability than the camera cloud occurrence but also follows similar seasonal variations (67% in winter and 44% in summer). This automatic low-cost detection of cloud occurrence is of interest in characterizing altitude observation sites, especially those that are not yet equipped with microphysical instruments and can be deployed to other high-altitude sites equipped with cameras. Full article

The dipole structure of the North Atlantic Oscillation (NAO) is examined in this study by defining the tilt of the NAO dipole centers on synoptic time scales. All the positive NAO phase (NAO+) and negative NAO phase (NAO−) events are divided into three tilting types according to their definition; namely, northeast–southwest (NE–SW), north–south symmetric (N–S, not tilted), and northwest–southeast (NW–SE) tilting NAO events. Then, the associated surface air temperature (SAT), geopotential height, zonal wind, and SST (surface sea temperature) anomalies of each type are examined. It is found that, for different asymmetric NAO tilt types, the local SATs exhibit significantly different distributions. The zonal wind has a good match with the NAO dipole tilt, which also includes the positive feedback of the NAO circulation. The basic zonal flow that removes the NAO days also exhibits a clear tilt structure that favors the tilt of the NAO dipole. Moreover, it is found that the Atlantic Multidecadal Oscillation (AMO) may be an important factor affecting the tilt of the NAO dipole. The AMO index has a significant 15-year lead for the NAO index and basic zonal flow index, with a high correlation coefficient, which might be seen as a precondition that indicates the tilt of the NAO events, especially on decadal or multidecadal time scales. However, the physical mechanisms and processes are still not fully understood. Full article

As part of more stringent energy targets in Switzerland, we witness the appearance of new green-certified dwellings while many existing dwellings have undergone energy efficiency measures. These measures have led to reduced energy consumption, but rarely consider their impact on indoor air quality. Consequently, such energy renovation actions can lead to an accumulation of radon in dwellings located in radon-prone areas at doses that can affect human health. This study compared the radon levels over 650 energy-efficient dwellings in western Switzerland between green-certified (Minergie) and energy-renovated dwellings, and analyzed the building characteristics responsible of this accumulation. We found that the newly green-certified dwellings had significantly lower radon level than energy-renovated, which were green- and non-green-certified houses (geometric mean 52, 87, and 105 Bq/m³, respectively). The new dwellings with integrated mechanical ventilation exhibited lower radon concentrations. Thermal retrofitting of windows, roofs, exterior walls, and floors were associated with a higher radon level. Compared to radon measurements prior to energy renovation, we found a 20% increase in radon levels. The results highlight the need to consider indoor air quality when addressing energy savings to avoid compromising occupants’ health, and are useful for enhancing the ventilation design and energy renovation procedures in dwellings. Full article

The emergence of new super-insulated buildings to reduce energy consumption places the quality of indoor air at the center of the debate. Among the indoor air pollutants, aldehydes are often present, and formaldehyde is of major interest regarding its multiple sources and its health impact. Therefore, French regulations expect to reduce formaldehyde concentrations below 10 μg m⁻³ in public buildings by 2023. Formaldehyde and other aldehydes were measured for two weeks during an intensive field campaign conducted in a school recently built and equipped with programmable dual-flow ventilation. Aldehydes were monitored with the ISO 16000-3 reference method based on sampling with 2,4-dinitrophenylhydrazine (DNPH) tubes while formaldehyde concentration was continuously measured by using a sensitive near real-time formaldehyde microanalyzer with a detection limit of 1 µg m⁻³. Formaldehyde was the major aldehyde. Its concentrations varied in the range of 2–25 µg m⁻³ and decreased by half when mechanical ventilation was ON, while the other ones were always below 5 µg m⁻³. In addition, an excellent agreement was observed between the different analytical techniques deployed to quantify formaldehyde levels. The microanalyzer was able to measure fast variations of formaldehyde concentration in the studied room, according to the building's ventilation periods. Full article

Unaware behaviors of occupants can affect energy consumption even more than incorrect installations and building envelope inefficiencies, with significant overconsumptions widely documented. Real time data and an effective and frequent billing of actual consumptions are required to reach an adequate awareness of energy consumption. From this point of view, the European Directive 2012/27/EU already imposed the use of metering and sub-metering systems, setting the minimum criteria for billing and related information based on real energy consumption data. To assess the ability of buildings to exploit new information and communication technologies (ICT) and sensitize both landlords and tenants to related savings, the new European Directive 2018/844/EU promotes the use of a smart readiness indicator. At the same time, basic information about indoor thermal comfort should be also gathered, aimed at avoiding that an excessive saving tendency can determine the onset of issues related to excessively low internal temperatures. In this paper, the authors address the problem of gathering, processing, and transmitting energy consumption and basic indoor air temperature data in the framework of an Internet of Things (IoT) integrated tool aimed at increasing residential user awareness through the use of consumption and benchmark indexes. Two case-studies in which thermal and electrical energy monitoring systems have been tested are presented and discussed. Finally, the suitability of the communication of energy consumption in terms of temporal, spatial, and typological aggregation has been evaluated. Full article

(1) Background: When it comes to estimating the annoyance potency of odors, European countries relate to different guidelines. In a previous study we compared complaint rates for different agricultural odors, but due to different guidelines, the results we obtained are hard to generalize. (2) Methods: We compare our findings on complaint rates to Dutch and German findings on annoyance rates, using diverse regression models. We also discuss whether the use of the polarity profile for hedonic odor quality could improve annoyance potency assessment. This is demonstrated by comparing the graphical profiles of two different odor types (swine and cattle). (3) Results: Official complaint rates are comparable to a percentage of annoyed residents. Confounder variables such as personal variables do not greatly contribute to annoyance. However, individual emission sites also showed an important influence on complaints and hence on annoyance. Considering the hedonic quality of odors via the polarity profile method for improving an annoyance potency assessment cannot be recommended when using the given state of the method. This is particularly true when it comes to the rating of specific odors, as the method then seems to lack reliability. (4) Conclusions: Where data on annoyance rates are lacking, complaint data could be used instead. Full article

Physical activity is an increasingly frequent part of our leisure time. Within this context, hiking is a popular form of tourism which has a positive impact on the quality of life. In spite of the importance of climate conditions for this recreational activity, relatively little research has been done on hiking from the perspective of climate and tourism. With this in mind in this paper we make the first detailed extensive assessment of climate preferences for the practice of hiking tourism in Spain. To this end a review of the theoretical/methodological body of literature on tourism climatology was conducted together with a survey aimed at evaluating the stated climate preferences of hiking tourists. The results are offered within the framework of international research on climate preferences for a range of tourism activities. The comparative analysis of these results with regard to those obtained in previous research highlights various similarities but also certain factors specific to hiking in Spain. Overall, the climate preferences of hiking tourists are similar to those of other segments of the tourism market in terms of the aesthetic and physical aspects of the climate, although they also have certain specific preferences as regards thermal aspects, especially regarding the optimal daily thermal conditions for hiking. The results obtained are useful for assessing the suitability of the climate for the practice of hiking tourism in Spain and for promoting proper management and planning of this leisure activity in tourist destinations, including the development of climate calendars detailing the most suitable times of the year for hiking at these destinations. These issues will be addressed in future research studies. Full article

The objective of this paper is to use remote sensing to measure on-road emissions and to examine the impact and usefulness of additional measurement devices at three sites. Supplementing remote sensing device (RSD) equipment with additional equipment increased the capture rate by almost 10%. Post-processing of raw data is essential to obtain useful and accurate information. A method is presented to identify vehicles with excessive emission levels (high emitters). First, an anomaly detection method is applied, followed by identification of cold start operating conditions using infrared vehicle profiles. Using this method, 0.6% of the vehicles in the full (enhanced) RSD data were identified as high emitters, of which 35% are likely in cold start mode where emissions typically stabilize to low hot running emission levels within a few minutes. Analysis of NO_x RSD data confirms that poor real-world NO_x performance of Euro 4/5 light-duty diesel vehicles observed around the world is also evident in Australian measurements. This research suggests that the continued dieselisation in Australia, in particular under the current Euro 5 emission standards and the more stringent NO₂ air quality criteria expected in 2020 and 2025, could potentially result in local air quality issues near busy roads. Full article

The paper focuses on the development of the method to estimate the mean characteristics of the atmospheric turbulence. Using an approach based on the shape of the energy spectrum of atmospheric turbulence over a wide range of spatial and temporal scales, the vertical profiles of optical turbulence are calculated. The temporal variability of the vertical profiles of turbulence under different low-frequency atmospheric disturbances is considered. Full article

In this study, AERONET (Aerosol Robotic Network) and EARLINET (European Aerosol Research Lidar Network) data from 17 collocated lidar and sun photometer stations were used to characterize the optical properties of aerosol and their types for the 2008–2018 period in various regions of Europe. The analysis was done on six cluster domains defined using circulation types around each station and their common circulation features. As concluded from the lidar photometer measurements, the typical aerosol particles observed during 2008–2018 over Europe were medium-sized, medium absorbing particles with low spectral dependence. The highest mean values for the lidar ratio at 532 nm were recorded over Northeastern Europe and were associated with Smoke particles, while the lowest mean values for the Angstrom exponent were identified over the Southwest cluster and were associated with Dust and Marine particles. Smoke (37%) and Continental (25%) aerosol types were the predominant aerosol types in Europe, followed by Continental Polluted (17%), Dust (10%), and Marine/Cloud (10%) types. The seasonal variability was insignificant at the continental scale, showing a small increase in the percentage of Smoke during spring and a small increase of Dust during autumn. The aerosol optical depth (AOD) slightly decreased with time, while the Angstrom exponent oscillated between “hot and smoky” years (2011–2015) on the one hand and “dusty” years (2008–2010) and “wet” years (2017–2018) on the other hand. The high variability from year to year showed that aerosol transport in the troposphere became more and more important in the overall balance of the columnar aerosol load. Full article

Studies in actual urban settings that integrate chemical reaction modeling, radiation, and particular emissions are mandatory to evaluate the effects of traffic-related air pollution on street canyons. In this paper, airflow patterns and reactive pollutant behavior for over 24 h, in a realistic urban canyon in Osaka City, Japan, was conducted using a computational fluid dynamics (CFD) model coupled with a chemical reaction model (CBM-IV). The boundary conditions for the CFD model were obtained from mesoscale meteorological and air quality models. Inherent street canyon processes, such as ground and wall radiation, were evaluated using a surface energy budget model of the ground and a building envelope model, respectively. The CFD-coupled chemical reaction model surpassed the mesoscale models in describing the NO, NO₂, and O₃ transport process, representing pollutants concentrations more accurately within the street canyon since the latter cannot capture the local phenomena because of coarse grid resolution. This work showed that the concentration of pollutants in the urban canyon is heavily reliant on roadside emissions and airflow patterns, which, in turn, is strongly affected by the heterogeneity of the urban layout. The CFD-coupled chemical reaction model characterized better the complex three-dimensional site and hour-dependent dispersion of contaminants within an urban canyon. Full article

Radar rainfall nowcasts are subject to many sources of uncertainty and these uncertainties change with the characteristics of a storm. The predictive skill of a radar rainfall nowcasting model can be difficult to understand as sometimes it appears to be perfect but at other times it is highly inaccurate. This hinders the decision making required for the early warning of natural hazards caused by rainfall. In this study we define radar spatial and temporal rainfall variability and relate them to the predictive skill of a nowcasting model. The short-term ensemble prediction system model is configured to predict 731 events with lead times of one, two, and three hours. The nowcasting skill is expressed in terms of six well-known indicators. The results show that the quality of radar rainfall nowcasts increases with the rainfall autocorrelation and decreases with the rainfall variability coefficient. The uncertainty of radar rainfall nowcasts also shows a positive connection with rainfall variability. In addition, the spatial variability is more important than the temporal variability. Based on these results, we recommend that the lead time for radar rainfall nowcasting models should change depending on the storm and that it should be determined according to the rainfall variability. Such measures could improve trust in the rainfall nowcast products that are used for hydrological and meteorological applications. Full article

In ultrasonic equipment (anemometers and thermometers), for the measurement of parameters of atmospheric turbulence, a standard algorithm that calculates parameters from temporary structural functions constructed on the registered data is usually used. The algorithm is based on the Kolmogorov–Obukhov law. The experience of using ultrasonic meters shows that such an approach can lead to significant errors. Therefore, an improved algorithm for calculating the parameters is developed, which allows more accurate estimation of the structural characteristics of turbulent fluctuations, with an error that is not more than 10%. The algorithm was used in the development of a new ultrasonic hardware-software complex, autonomous meteorological complex AMK-03-4, which differs from similar measuring instruments of turbulent atmosphere parameters by the presence of four identical ultrasonic anemometers. The design of the complex allows not only registration of the characteristics of turbulence, but also measurement of the statistical characteristics of the spatial derivatives of turbulent temperature fluctuations and orthogonal components of wind speed along each of the axes of the Cartesian coordinate system. This makes it possible to investigate the space–time structure of turbulent meteorological fields of the surface layer of the atmosphere for subsequent applications in the Monin–Obukhov similarity theory and to study turbulent coherent structures. The new measurement data of the spatial derivatives of temperature at stable stratification (at positive Monin–Obukhov parameters) were obtained, at which the behavior of the derivatives was been investigated earlier. In the most part of the interval of positive Monin–Obukhov parameters, the vertical derivative of the temperature is close to a constant value. This fact can be considered as a new significant result in similarity theory. Full article

Due to their rarity and intensity, Mediterranean Tropical-Like Cyclones (TLCs; also known as medicanes) have been a subject of study over the last decades and lately the interest has undoubtedly grown. The current study investigates a well-documented TLC event crossed south Sicily on November 7–8, 2014 and the added value of higher spatial horizontal resolution through a physics parameterization sensitivity analysis. For this purpose, Weather Research and Forecasting model (version 3.9) is used to dynamically downscale ECMWF Re-Analysis (version 5) (ERA5) reanalysis 31 km spatial resolution to 16 km and 4 km, as parent and inner domain, respectively. In order to increase the variability and disparity of the results, spectral nudging was implemented on both domains and the outputs were compared against satellite observations and ground-based stations. Although, the study produces mixed results, there is a clear indication that the increase of resolution benefits specific aspects of the cyclone, while it deteriorates others, based on both ground and upper air analyses. The sensitivity of the parent domain displays an overall weak variability while the simulations demonstrate a positive time-lag predicting a less symmetric cyclone with weak warm core. On the contrary, inner domain analysis shows stronger variability between the model simulations reproducing more distinct clear tropical characteristics with less delayed TLC development for most of the experiments. Full article

In recent years, air pollution has become an important public health concern. The high concentration of fine particulate matter with diameter less than 2.5 µm (PM_2.5) is known to be associated with lung cancer, cardiovascular disease, respiratory disease, and metabolic disease. Predicting PM_2.5 concentrations can help governments warn people at high risk, thus mitigating the complications. Although attempts have been made to predict PM_2.5 concentrations, the factors influencing PM_2.5 prediction have not been investigated. In this work, we study feature importance for PM_2.5 prediction in Tehran’s urban area, implementing random forest, extreme gradient boosting, and deep learning machine learning (ML) approaches. We use 23 features, including satellite and meteorological data, ground-measured PM_2.5, and geographical data, in the modeling. The best model performance obtained was R² = 0.81 (R = 0.9), MAE = 9.93 µg/m³, and RMSE = 13.58 µg/m³ using the XGBoost approach, incorporating elimination of unimportant features. However, all three ML methods performed similarly and R² varied from 0.63 to 0.67, when Aerosol Optical Depth (AOD) at 3 km resolution was included, and 0.77 to 0.81, when AOD at 3 km resolution was excluded. Contrary to the PM_2.5 lag data, satellite-derived AODs did not improve model performance. Full article

There is a paucity of comprehensive air quality data from urban areas in the Middle East. In this study, portable instrumentation was used to measure size-fractioned aerosol number, mass, and black carbon concentrations in Amman and Zarqa, Jordan. Submicron particle number concentrations at stationary urban background sites in Amman and Zarqa exhibited a characteristic diurnal pattern, with the highest concentrations during traffic rush hours (2–5 × 10⁴ cm⁻³ in Amman and 2–7 × 10⁴ cm⁻³ in Zarqa). Super-micron particle number concentrations varied considerably in Amman (1–10 cm⁻³). Mobile measurements identified spatial variations and local hotspots in aerosol levels within both cities. Walking paths around the University of Jordan campus showed increasing concentrations with proximity to main roads with mean values of 8 × 10⁴ cm⁻³, 87 µg/m³, 62 µg/m³, and 7.7 µg/m³ for submicron, PM₁₀, PM_2.5, and black carbon (BC), respectively. Walking paths in the Amman city center showed moderately high concentrations (mean 10⁵ cm⁻³, 120 µg/m³, 85 µg/m³, and 8.1 µg/m³ for submicron aerosols, PM₁₀, PM_2.5, and black carbon, respectively). Similar levels were found along walking paths in the Zarqa city center. On-road measurements showed high submicron concentrations (>10⁵ cm⁻³). The lowest submicron concentration (<10⁴ cm⁻³) was observed near a remote site outside of the cities. Full article

This review paper explores the field of mesoscale to microscale modeling over complex terrain as it traverses multiple so-called gray zones. In an attempt to bridge the gap between previous large-scale and small-scale modeling efforts, atmospheric simulations are being run at an unprecedented range of resolutions. The gray zone is the range of grid resolutions where particular features are neither subgrid nor fully resolved, but rather are partially resolved. The definition of a gray zone depends strongly on the feature being represented and its relationship to the model resolution. This paper explores three gray zones relevant to simulations over complex terrain: turbulence, convection, and topography. Taken together, these may be referred to as the gray continuum. The focus is on horizontal grid resolutions from ∼10 km to ∼10 m. In each case, the challenges are presented together with recent progress in the literature. A common theme is to address cross-scale interaction and scale-awareness in parameterization schemes. How numerical models are designed to cross these gray zones is critical to complex terrain applications in numerical weather prediction, wind resource forecasting, and regional climate modeling, among others. Full article

Tailpipe emissions of a pool of 13 Euro 6b light-duty vehicles (eight diesel and five gasoline-powered) were measured over an extensive experimental campaign that included laboratory (chassis dynamometer), and on-road tests (using a portable emissions measurement system). The New European Driving Cycle (NEDC) and the Worldwide harmonised Light-duty vehicles Test Cycle (WLTC) were driven in the laboratory following standard and extended testing procedures (such as low temperatures, use of auxiliaries, modified speed trace). On-road tests were conducted in real traffic conditions, within and outside the boundary conditions of the regulated European Real-Driving Emissions (RDE) test. Nitrogen oxides (NO_X), particle number (PN), carbon monoxide (CO), total hydrocarbons (HC), and carbon dioxide (CO₂) emission factors were developed considering the whole cycles, their sub-cycles, and the first 300 s of each test to assess the cold start effect. Despite complying with the NEDC type approval NO_X limit, diesel vehicles emitted, on average, over the WLTC and the RDE 2.1 and 6.7 times more than the standard limit, respectively. Diesel vehicles equipped with only a Lean NO_X trap (LNT) averaged six and two times more emissions over the WLTC and the RDE, respectively, than diesel vehicles equipped with a selective catalytic reduction (SCR) catalyst. Gasoline vehicles with direct injection (GDI) emitted eight times more NO_X than those with port fuel injection (PFI) on RDE tests. Large NO_X emissions on the urban section were also recorded for GDIs (122 mg/km). Diesel particle filters were mounted on all diesel vehicles, resulting in low particle number emission (~10¹⁰ #/km) over all testing conditions including low temperature and high dynamicity. GDIs (~10¹² #/km) and PFIs (~10¹¹ #/km) had PN emissions that were, on average, two and one order of magnitude higher than for diesel vehicles, respectively, with significant contribution from the cold start. PFIs yielded high CO emission factors under high load operation reaching on average 2.2 g/km and 3.8 g/km on WLTC extra-high and RDE motorway, respectively. The average on-road CO₂ emissions were ~33% and 41% higher than the declared CO₂ emissions at type-approval for diesel and gasoline vehicles, respectively. The use of auxiliaries (AC and lights on) over the NEDC led to an increase of ~20% of CO₂ emissions for both diesel and gasoline vehicles. Results for NO_X, CO and CO₂ were used to derive average on-road emission factors that are in good agreement with the emission factors proposed by the EMEP/EEA guidebook. Full article

Air pollution is becoming a prominent social problem in fast-growing Asian economies. Taking the Bangkok Metropolitan Region (BMR) as a case, we conducted an observational study of fine particulate matter (PM_2.5) and acid deposition, consisting of their continuous monitoring at two sites. To find the major contributing sources of PM_2.5, the PM composition data were analyzed by a receptor modeling approach while the pollution load from BMR sources to the air was characterized by an emission inventory. Our data show generally alarming levels of PM_2.5 in the region, of which transportation and biomass burning are two major sources. In this paper, we present a general overview of our observational findings, contrast the scientific information with the policy context of air quality management in BMR, and discuss policy implications. In BMR, where a set of conventional regulatory instruments on air quality management are already in place, a solution for the air pollution problem should lie in a combination of air quality regulation and other policies, such as energy and agricultural policies. Full article

The uptake of dinitrogen pentoxide (N₂O₅) on aerosols affects the nocturnal removal of NO_x and particulate nitrate formation in the atmosphere. This study investigates N₂O₅ uptake processes using field observations from an urban site in Beijing during April–May 2017, a period characterized by dry weather conditions. For the first time, a very large N₂O₅ uptake rate (k(N₂O₅) up to ~0.01 s⁻¹) was observed during a sand storm event, and the uptake coefficient (γ(N₂O₅)) was estimated to be 0.044. The γ(N₂O₅) in urban air masses was also determined and exhibited moderate correlation (r = 0.68) with aerosol volume to surface ratio (V_a/S_a), but little relation to aerosol water, nitrate, and chloride, a finding that contrasts with previous results. Several commonly used parameterizations of γ(N₂O₅) underestimated the field-derived γ(N₂O₅). A new parameterization is suggested for dry conditions, which considers the effect of V_a/S_a, temperature, and relative humidity. Full article

Chemical characterization of fine atmospheric particles (PM_2.5) is important for effective reduction of air pollution. This work analyzed PM_2.5 samples collected in Yangzhou, China, during 2016. Ionic species, organic matter (OM), elemental carbon (EC), and trace metals were determined, and an Aerodyne soot-particle aerosol mass spectrometer (SP-AMS) was introduced to determine the OM mass, rather than only organic carbon mass. We found that inorganic ionic species was dominant (~52%), organics occupied about 1/4, while trace metals (~1%) and EC (~2.1%) contributed insignificantly to the total PM_2.5 mass. Water-soluble OM appeared to link closely with secondary OM, while water-insoluble OM correlated well with primary OM. The PM_2.5 concentrations were relatively low during summertime, while its compositions varied little among different months. Seasonal variations of water-soluble organic nitrogen (WSON) concentrations were not significant, while the mass contributions of WSON to total nitrogen were remarkably high during summer and autumn. WSON was found to associate better with secondary sources based on both correlation analyses and principle component analyses. Analyses of potential source contributions to WSON showed that regional emissions were dominant during autumn and winter, while the ocean became relatively important during spring and summer. Full article

The variability and mechanisms of multi-decadal megadroughts over eastern China during the last millennium were investigated using a control, full-forcing, and four sensitivity experiments from the Community Earth System Model (CESM) Last Millennium Ensemble (LME) archive. The model simulated megadroughts have comparable magnitudes and durations with those derived from reconstructed proxy data, although the megadroughts are not temporally synchronous. In all experiments, the megadroughts exhibit similar spatial structures, corresponding to a weakening of the East Asia summer monsoon (EASM) and a strengthening of the East Asia winter monsoon (EAWM). The results show that internal climate variability within the coupled climate system plays an essential role in triggering megadroughts, while different external forcings may contribute to persistence and modify the anomaly patterns of megadroughts. A pattern of meridional tripolar (warm-cold-warm) sea surface temperature (SST) anomalies in the western Pacific stretching from the equator to high latitude is responsible for the EASM weakening and EAWM strengthening. The weakening of the EASM and strengthening of the EAWM are essentially caused by negative SST anomalies over the northwestern Pacific and positive SST anomalies over the equatorial western Pacific, which are associated with a La Niña-like SST gradient across the tropical Pacific. The external forcings prolong the megadroughts through maintenance of the meridional tripolar SST anomalies and enlarge the megadrought spatial extent by magnifying the meridional tripolar SST anomalies. Full article

Consistent streamflow forecasts play a fundamental part in flood risk mitigation. Population increase and water cycle intensification are extending not only globally but also among Pakistan’s water resources. The frequency of floods has increased in the last few decades in the country, which emphasizes the importance of efficient practices needed to adopt for various aspects of water resource management such as reservoir scheduling, water sustainability, and water supply. The purpose of this study is to develop a novel hybrid model for streamflow forecasting and validate its efficiency at the upper Indus basin (UIB), Pakistan. Maximum streamflow in the River Indus from its upper mountain basin results from melting snow or glaciers and climatic unevenness of both precipitation and temperature inputs, which will, therefore, affect rural livelihoods at both a local and a regional scale through effects on runoff in the Upper Indus basin (UIB). This indicates that basins receive the bulk of snowfall input to sustain the glacier system. The present study will help find the runoff from high altitude catchments and estimated flood occurrence for the proposed and constructed hydropower projects of the Upper Indus basin (UIB). Due to climate variability, the upper Indus basin (UIB) was further divided into three zone named as sub-zones, zone one (z1), zone two (z2), and zone three (z3). The hybrid models are designed by incorporating artificial intelligence (AI) models, which includes Feedforward backpropagation (FFBP) and Radial basis function (RBF) with decomposition methods. This includes a discrete wavelet transform (DWT) and ensemble empirical mode decomposition (EEMD). On the basis of the autocorrelation function and the cross-correlation function of streamflow, precipitation and temperature inputs are selected for all developed models. Data have been analyzed by comparing the simulation outputs of the models with a correlation coefficient (R), root mean square errors (RMSE), Nash-Sutcliffe Efficiency (NSE), mean absolute percentage error (MAPE), and mean absolute errors (MAE). The proposed hybrid models have been applied to monthly streamflow observations from three hydrological stations and 17 meteorological stations in the UIB. The results show that the prediction accuracy of the decomposition-based models is usually better than those of AI-based models. Among the DWT and EEMD based hybrid model, EEMD has performed significantly well when compared to all other hybrid and individual AI models. The peak value analysis is also performed to confirm the results’ precision rate during the flood season (May-October). The detailed comparative analysis showed that the RBFNN integrated with EEMD has better forecasting capabilities as compared to other developed models and EEMD-RBF can capture the nonlinear characteristics of the streamflow time series during the flood season with more precision. Full article

The Yangtze River Basin is an El Niño–Southern Oscillation (ENSO)-sensitive region, prone to floods and droughts. Hydrological records were collected to examine the temporal and spatial distribution of runoff in this drainage basin. An apparent difference in runoff variations between the upper and mid-lower Yangtze reaches was detected in response to ENSO. The upper basin usually experiences floods or droughts during the summer of ENSO developing years, while the mid-lower runoff variations tend to coincide with ENSO decaying phases. Composite analysis is employed to investigate the underlying mechanism for the teleconnection between the specific phases of the ENSO cycle and Yangtze runoff variation. Results show that the Western Pacific Subtropical High (WPSH) exhibits large variability on its western side in summer with different ENSO phases, thus resulting in a contrasting influence between the upper and mid-lower Yangtze floods and droughts. During the central Pacific-La Niña developing summers, the WPSH is significantly enhanced with its westward extension over the Yangtze upper basin. Anomalous water vapor converges in its northwest edge thus favoring upper-basin flooding. Meanwhile, the mid-lower reaches are controlled by the WPSH, and the local rainfall is not obvious. In addition, when the El Niño decaying phases occur, the WPSH denotes a westward extending trend and the position of its ridge line shifts to the mid-lower Yangtze reaches. The southwest moisture cannot extend to the upper basin but converges in the mid-lower basin. Accompanied by the anomalous 100 hPa South Asia High and lower-tropospheric Philippines anticyclone movements, this upper–middle–lower configuration acts as a key bridge linking ENSO and Yangtze floods and droughts. Full article

This study investigated spatial factors controlling CO₂, CH₄, and N₂O fluxes and compared global warming potential (GWP) among undrained forest (UDF), drained forest (DF), and drained burned land (DBL) on tropical peatland in Central Kalimantan, Indonesia. Sampling was performed once within two weeks in the beginning of dry season. CO₂ flux was significantly promoted by lowering soil moisture and pH. The result suggests that oxidative peat decomposition was enhanced in drier position, and the decomposition acidify the peat soils. CH₄ flux was significantly promoted by a rise in groundwater level, suggesting that methanogenesis was enhanced under anaerobic condition. N₂O flux was promoted by increasing soil nitrate content in DF, suggesting that denitrification was promoted by substrate availability. On the other hand, N₂O flux was promoted by lower soil C:N ratio and higher soil pH in DBL and UDF. CO₂ flux was the highest in DF (241 mg C m⁻² h⁻¹) and was the lowest in DBL (94 mg C m⁻² h⁻¹), whereas CH₄ flux was the highest in DBL (0.91 mg C m⁻² h⁻¹) and was the lowest in DF (0.01 mg C m⁻² h⁻¹), respectively. N₂O flux was not significantly different among land uses. CO₂ flux relatively contributed to 91–100% of GWP. In conclusion, it is necessary to decrease CO₂ flux to mitigate GWP through a rise in groundwater level and soil moisture in the region. Full article

Crop residue burning negatively impacts both the environment and human health, whether in the aspect of air pollution, regional and global climate change, or transboundary air pollution. Accordingly, this study aims to assess the level of air pollutant emissions caused by the rice residue open burning activities in 2018, by analyzing the remote sensing information and country specific data. This research also aims to analyze the trend of particulate matter 10 microns or less in diameter (PM₁₀) concentration air quality sites in provinces with large paddy rice planting areas from 2010–2017. According to the results, 61.87 megaton (Mt) of rice residue were generated, comprising 21.35 Mt generated from the irrigated fields and 40.53 Mt generated from the rain-fed field. Only 23.0% of the total rice residue generated were subject to open burning—of which nearly 32% were actually burned in the fields. The emissions from such rice residue burning consisted of: 5.34 ± 2.33 megaton (Mt) of CO₂, 44 ± 14 kiloton (kt) of CH₄, 422 ± 179 kt of CO, 2 ± 2 kt of NO_X, 2 ± 2 kt of SO₂, 38 ± 22 kt of PM_2.5, 43 ± 29 kt of PM₁₀, 2 ± 1 kt of black carbon (BC), and 14 ± 5 kt of organic carbon (OC). According to the air quality trends, the results shows the higher level of PM₁₀ concentration was due to the agricultural burning activities, as reflected in the higher monthly averages of the months with the agricultural burning, by around 1.9–2.1 times. The result also shows the effect of government’s policy for farmers on the crop burning activities and air quality trends. Full article

The impact of snow darkening by deposition of light-absorbing aerosols (LAAs) on snow cover over the Himalayas–Tibetan Plateau (HTP) and the influence on the Asian summer monsoon were investigated using the NASA Goddard Earth Observing System Model Version 5 (GEOS-5). The authors found that during April–May–June, the deposition of LAAs on snow led to a reduction in surface albedo, initiating a sequence of feedback processes, starting with increased net surface solar radiation, rapid snowmelt in the HTP and warming of the surface and upper troposphere, followed by enhanced low-level southwesterlies and increased dust loading over the Himalayas–Indo-Gangetic Plain. The warming was amplified by increased dust aerosol heating, and subsequently amplified by latent heating from enhanced precipitation over the Himalayan foothills and northern India, via the elevated heat pump (EHP) effect during June–July–August. The reduced snow cover in the HTP anchored the enhanced heating over the Tibetan Plateau and its southern slopes, in conjunction with an enhancement of the Tibetan Anticyclone, and the development of an anomalous Rossby wave train over East Asia, leading to a weakening of the subtropical westerly jet, and northward displacement and intensification of the Mei-Yu rain belt. The authors’ results suggest that the atmosphere-land heating induced by LAAs, particularly desert dust, plays a fundamental role in physical processes underpinning the snow–monsoon relationship proposed by Blanford more than a century ago. Full article

The El Niño–Southern Oscillation (ENSO) is the strongest interannual air–sea coupled variability mode in the tropics, and substantially impacts the global weather and climate. Hence, it is important to improve our understanding of the ENSO variability. Besides the well-known air–sea interaction process over the tropical Pacific, recent studies indicated that atmospheric and oceanic forcings outside the tropical Pacific also play important roles in impacting and modulating the ENSO occurrence. This paper reviews the impacts of the atmosphere–ocean variability outside the tropical Pacific on the ENSO variability, as well as their associated physical processes. The review begins with the contribution of the atmosphere–ocean forcings over the extratropical North Pacific, Atlantic, and Indian Ocean on the ENSO occurrence. Then, an overview of the extratropical atmospheric forcings over the Northern Hemisphere (including the Arctic Oscillation and the Asian monsoon systems) and the Southern Hemisphere (including the Antarctic Oscillation and the Pacific–South American teleconnection), on the ENSO occurrence, is presented. It is shown that the westerly (easterly) wind anomaly over the tropical western Pacific is essential for the occurrence of an El Niño (a La Niña) event. The wind anomalies over the tropical western Pacific also play a key role in relaying the impacts of the atmosphere–ocean forcings outside the tropical Pacific on the ENSO variability. Finally, some relevant questions, that remain to be explored, are discussed. Full article

Rate coefficients at ambient temperature and atmospheric pressure for the reaction of ozone with 2-methoxypropene (2-MPE) and 2-ethoxypropene (2-EPE) were determined in an evacuable 100 L Teflon reaction chamber using absolute and relative rate methods. The product experiments were carried out using a 50 L Teflon reaction chamber in conjunction with FTIR as the detection technique. The rate coefficients (k in units of cm³ molecule⁻¹ s⁻¹) obtained are 1.18 ± 0.13 × 10⁻¹⁷ and 1.89 ± 0.23 × 10⁻¹⁷ for reactions with 2-MPE and 2-EPE, respectively. The effects of the alkoxy group on the gas-phase reactivity of alkyl vinyl ethers toward ozone are compared and discussed. The major ozonolysis products are methyl acetate, formaldehyde and CO₂ for 2-MPE, and ethyl acetate, formaldehyde and CO₂ for 2-EPE. Possible mechanisms for the two vinyl ethers are proposed based on the observed reaction products. Additionally, atmospheric lifetimes of 32 h and 21 h for 2-MPE and 2-EPE were estimated based on the measured rate constants and the ambient tropospheric concentration of ozone, respectively. The obtained values of the lifetimes indicate that the reaction with ozone is an important loss process for these vinyl ethers in the atmosphere, especially in polluted areas. Full article

Bioaerosol emissions arising from biowaste treatment are an issue of public concern. To better characterise the bioaerosols, and to assess a range of measurement methods, we aerosolised green waste compost under controlled conditions. Viable and non-viable Andersen samplers, cyclone samplers and a real time bioaerosol detection system (Spectral Intensity Bioaerosol Sensor (SIBS)) were deployed simultaneously. The number-weighted fraction of fluorescent particles was in the range 22–26% of all particles for low and high emission scenarios. Overall fluorescence spectral profiles seen by the SIBS exhibited several peaks across the 16 wavelength bands from 298 to 735 nm. The size-fractionated endotoxin profile showed most endotoxin resided in the 2.1–9 μm aerodynamic diameter fraction, though up to 27% was found in a finer size fraction. A range of microorganisms were detected through culture, Matrix Assisted Laser Desorption and Ionisation Time of Flight Mass Spectrometry (MALDI-TOF) and quantitative polymerase chain reaction (qPCR), including Legionella pneumophila serogroup 1. These findings contribute to our knowledge of the physico-chemical and biological characteristics of bioaerosols from composting sites, as well as informing future monitoring approaches and data interpretation for bioaerosol measurement. Full article

The temporal and spatial distributions of tropospheric ozone and its precursors (NO₂, CO, HCHO) are analyzed over Guangxi (GX) in South China. We used tropospheric column ozone (TCO) from the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) onboard the Aura satellite (OMI/MLS), NO₂ and HCHO from OMI and CO from the Measurements of Pollution in the Troposphere (MOPITT) instrument in the period 2005–2016. The TCO shows strong seasonality, with the highest value in spring and the lowest value observed in the monsoon season. The seasonal variation of HCHO is similar to that of TCO, while NO₂ and CO show slightly different patterns with higher values in spring and winter compared to lower values in autumn and summer. The surface ozone, NO₂ and CO observed by national air quality monitoring network sites are also compared with satellite-observed TCO, NO₂ and CO, showing good agreement for NO₂ and CO but a different seasonal pattern for ozone. Unlike TCO, surface ozone has the highest value in autumn and the lowest value in winter. To reveal the difference, the vertical profiles of ozone and CO from the measurement of ozone and water vapor by airbus in-service aircraft (MOZAIC) observations over South China are also examined. The seasonal averaged vertical profiles of ozone and CO show obvious enhancements at 2–6 km altitudes in spring. Furthermore, we investigate the dependence of TCO and surface ozone on meteorology and transport in detail along with the ECMWF reanalysis data, Tropical Rainfall Measuring Mission (TRMM) 3BV42 dataset, OMI ultraviolet index (UV index) dataset, MODIS Fire Radiative Power (FRP) and back trajectory. Our results show that the wind pattern at 800 hPa plays a significant role in determining the seasonality of TCO over GX, especially for the highest value in spring. Trajectory analysis, combined with MODIS FRP suggests that the air masses that passed through the biomass burning (BB) region of Southeast Asia (SEA) induced the enhancement of TCO and CO in the upper-middle troposphere in spring. However, the seasonal cycle of surface ozone is associated with wind patterns at 950 hPa, and the contribution of the photochemical effect is offset by the strong summer monsoon, which results in the maximum surface ozone concentration in post-monsoon September. The variations in the meteorological conditions at different levels and the influence of transport from SEA can account for the vertical distribution of ozone and CO. We conclude that the seasonal distribution of TCO results from the combined impact of meteorology and long-term transport. Full article

In the Netherlands, there will be an urgent need for additional housing by the year 2040, which mainly has to be realized within the existing built environment rather than in the spatial extension of cities. In this data-driven study, we investigated the effects of different urban planning strategies on heat stress for the current climate and future climate scenarios (year 2050) for the urban agglomeration of The Hague. Heat stress is here expressed as the number of days exceeding minimum temperatures of 20 °C in a year. Thereto, we applied a diagnostic equation to determine the daily maximum urban heat island based on routine meteorological observations and straightforward urban morphological properties including the sky-view factor and the vegetation fraction. Moreover, we utilized the Royal Netherlands Meteorological Institute’s (KNMI) climate scenarios to transform present-day meteorological hourly time series into the future time series. The urban planning strategies differ in replacing low- and mid-rise buildings with high-rise buildings (which reduces the sky-view factor), and constructing buildings on green areas (which reduces the vegetation fraction). We found that, in most cases, the vegetation fraction is a more critical parameter than the sky-view factor to minimize the extra heat stress incurred when densifying the neighbourhood. This means that an urban planning strategy consisting of high-rise buildings and preserved green areas is often the best solution. Still, climate change will have a larger impact on heat stress for the year 2050 than the imposed urban densification. Full article

The Maritime Continent (MC) is positioned between the Asian and Australian summer monsoons zone. The complex topography and shallow seas around it are major challenges for the climate researchers to model and understand it. It is also the centre of the tropical warm pool of Southeast Asia (SEA) and therefore the MC gets extra attention of the researchers. The monsoon in this area is affected by inter-scale ocean-atmospheric interactions such as the El-Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the Madden-Julian Oscillation (MJO). Monsoon rainfall in the MC (especially in Indonesia and Malaysia) profoundly exhibits its variability dependence on ocean-atmospheric phenomena in this region. This monsoon shift often introduces to dreadful events like biomass burning (BB) in Southeast Asia (SEA) in which some led to severe trans-boundary haze pollution events in the past. In this study, the BB episode of 2015 in the MC is highlighted and discussed. Observational satellite datasets are tested by performing simulations with the numerical weather prediction (NWP) model WRF-ARW (Weather Research and Forecast—Advanced research WRF). Observed and model datasets are compared to study the surface air temperature and precipitation (rainfall) anomalies influenced by ENSO, IOD, and MJO. Links amongst these influences have been recognised and the delayed precipitation of the regular monsoon in the MC due to their influence during the 2015 BB episode is explained and accounted for, which eventually led to the intensification of fire and a severe haze. Full article

This paper explores the impact of choice of ventilation setting (“window open”, “new (external) air” and “recirculate”) on in-vehicle carbon monoxide exposures for commuters travelling by car at different times of the day (morning, midday, and evening) and different seasons (warm and cool) in Auckland, New Zealand. Three near-identical vehicles travelled in close proximity to each other on the same three “loops” out and into the city three times a day, each with a different ventilation setting. Concentrations of carbon monoxide were recorded using portable monitors placed inside each of the vehicles. The season was not found to be a significant factor. However, mean concentrations varied across ventilation settings by the time of day, typically peaking during the morning commute. The mean concentrations were significantly different between ventilation settings, with the recirculate setting found to result in a higher in-vehicle concentration than either new air or windows open but also heavily dependent on the initial in-vehicle concentration. However, this setting was the most effective at avoiding concentration spikes, especially when idling at intersections; an isolated peak event reaching 170 ppm was observed with the “new air” setting when following immediately behind an old, poorly-tuned, and visibly-emitting vehicle. This study suggests that having the windows open is the best setting for maintaining low in-cabin air pollution levels but that recirculate should be used in anticipation of congested conditions. Full article